This invention relates to utility towers. More particularly, this invention relates to towers of the type utilized for radio and telephone communication.
A typical radio transmission lattice tower comprises a plurality of weldments which are structurally similar to a common triangular truss having three equi-laterally arranged cords, and having a series of alternately angled tie braces or a lattice web spanning therebetween in a typically xe2x80x9czig zaggedxe2x80x9d pattern. Upper and lower ends of such weldment are typically provided with bolt receiving mounting plates for bolted interconnection with other similar weldments in a vertically extending series.
A drawback or deficiency of lattice tower assemblies which are configured as described above is that they lack space economy during shipment, typically requiring utilization of several flatbed trucks or trailers for transporting such tower segments from a steel fabrication facility to a tower erection site.
The instant inventive lattice tower solves or ameliorates problems noted above by providing series of triplets of substantially flat weldments which are compactly transportable and which are easily assembleable in the field at a tower erection site.
The instant inventive lattice tower preferably comprises a plurality of substantially flat and substantially identical weldments. Each weldment of the inventive lattice tower preferably includes a pole, upper and lower mounting plates welded to upper and lower ends of the pole, a first series or plurality of eye plates welded to the pole in a vertically extending pattern along the length of the pole, a lattice or web of brace members welded to the pole at their proximal ends and extending outwardly from the pole, and a second series or plurality of eye plates welded to the distal end of the web. Necessarily, the second plurality of eye plates is arranged in a vertically extending pattern matching the pattern of the first plurality of eye plates.
The pole of the above described weldment preferably comprises a sectioned steel pipe or tube, and the preferred mounting plates welded to upper and lower ends of the pole sections are preferably vertically apertured for receipt of helically threaded nut and bolt combinations. Abutting alignments of the mounting plates allows several similarly configured poles to be securely bolted together in a vertically extending series matching a desired height of the lattice tower. Pin and sleeve joints, slip joints, and lap joints may be suitably substituted for the preferred abuttingly attached mounting plates.
The first plurality of eye plates of the above described weldment are preferably oriented so that they extend at 600xc2x0 angles away from the plane of the web. Such eye plates are preferably double apertured. The second plurality of eye plates welded to the distal end of the web is similarly preferably double apertured. The double apertures of the eye plates allows one pair of overlying eyes to be manipulated by a lever (e.g., a rod or punch) rod for plate alignment, allowing the other pair to easily receive an attachment bolt.
Triplets of substantially identical weldments such as described above are conveniently boltable together to form substantially cylindrical structures having cross sectional shapes approximating equi-lateral triangles, such structures being similar to triangular trusses. By abuttingly attaching pole mounting plates, such segments form the vertically extending series of weldments and sections, forming the inventive lattice tower.
A key advantage of the instant inventive lattice tower is that its individual substantially flat weldments are stackable in stratified lots upon truck or trailer beds for compact cost effective transportation from steel fabrication facilities to tower erection sites.
Accordingly, an object of the instant inventive lattice tower is the provision of substantially flat weldments which are assembleable in the field into equi-lateral triangular tower segments, and which are compactly and conveniently stackable and transportable.
Other and further objects, benefits, and advantages of the present invention will become known to those skilled in the art upon review of the Detailed Description which follows, and upon review of the appended drawings.